[Consumer] Added fabric client unittests

common/cpp/include/unittests/MockFabric.h

consumer/api/cpp/CMakeLists.txt

consumer/api/cpp/src/fabric_consumer_client.cpp

consumer/api/cpp/src/fabric_consumer_client.h

consumer/api/cpp/unittests/test_fabric_consumer_client.cpp

...r/src/receiver_data_server/net_server/rds_fabric_server.h

...eceiver_data_server/net_server/test_rds_fabric_server.cpp